US1136062A - Electropneumatic brake. - Google Patents

Description

W. v. TURNER.

ELECTROPNEUMATIC BRAKE.

APPLICATION FILED AUG-Z6, 1912- LWE UW; I Patented A r. 20, 1915..

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W. V. TURNER.

-ELECTRQPNEUMATIC BRAKE.

APPLICATION FILED AUG.26, 1912.

Patented Apr. 20, 1915.

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MAGNET RELEASE PIPES; 2's canrsgk.

WITNESSES INVENTOR W. V. TURNER.

ELECTROPNEUMATIC BRAKE. fi-wmfifiwmfigm. APPLICATION map AUG-26, 1912. Patented APR 20, 1915.

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WITNESSES INVENTOR W. V. TURNER.

ELEGTROPNEUMATlC BRAKE.

APPLICATION FILED AUG.26. 1912.

Patented Apr. 20, 1915.

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wire earn-e WALTER V. TURNER, OF EDGEWOOD, PENNSYLVANIA, ASSIGNOR TO THE WESTING- HOUSE AIR, BRAKE COMPANY, OF WILMERJDING, PENNSYLVANIA, A CORPORATION OF EENNSYLVANIA.

ELECTROPNE'UMATIC BRAKE.

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Specification of Letters Patent.

Patented Apr. 2%, T315;

Application filed August 26, 1912. Serial No. 716,963.

an improved electro-pneumatic control valve mechanism in which the pressure in an application chamber controls the supply of fluid to and from the brake cylinder.

Another object of my invention is to provide means for holding the application valve mechanism in emergency position regardless of the brake cylinder pressure.

Another object of my invention is to provide means controlled by the application valve mechanism for supplying fluid to the brake cylinder to effect an emergency high pressure application of the brakes.

Another object of my invention is to provide an application valve mechanism having two positions, one for efi'ecting a service application of the brakes, and the other for effecting an emergency application of the brakes.

Still another object of my invention consists in providing a brake controlling valve mechanism having an application chamber and in which-the equalizin pressure ma be adjusted to suit the class 0? service in W ich the same is. employed.

Other objects and advantages of the invention' will appear in the more detailed description of the invention hereafter set forth.

In the accompanying drawings; Figure 1 is a diagrammatic view of an electro-pneumatic brake apparatus embodying my improvements as applied to two cars; Fig. 2 a schematic diagram of the electric wiring circuits; Fig. 3 a central sectional diagrammatic view of the electro-pneumatic control valve showing the parts in normal release position; Fig. 4 a similar view, showing the parts in electric service application posipassage 42.

. tion; Fig. 5 a similar view, showing the parts in electric emergency application position; Fig. 6 a sectional view of the graduated release cap in position for cutting out the graduated release; and Fig. 7 a sectional View of the equalizing piston cap in the position for connecting in the additional application chamber.

As shown in Figs. 3 to 5, the electropneumatic control valve device may comprise an application valve mechanism 1, equalizing valve mechanism 2, quick action valve mechanism 3, emergency valve mechanism 4, emergency switch portion 5, protection valve device 6, high pressure emergency valve mechanism 7, electric release magnet 8, electric service magnet 9, and electric emergency magnet 10. p The application valve mechanism 1 comprises a piston 11 dividing the piston chamber into two chambers 12 and 13, the cham- .ber 12 being in communication with a passage 14 leading to an application chamber 15. The piston 11 operates an application valve 16 contained in valve chamber 17 which is connected by a pipe 18 to the main reservoir pipe line 19-. Said piston also controls a release valve 20 contained in valve chamber 21 which is connected to the brake cylinder through a passage 22 leading to passage 23. Contained in piston chamber 24. and mounted on the piston stem 25 of the piston 11 is a piston '26 adapted to separate the piston chamber 13 from the valve chamber 21.

The equalizing valve mechanism 2 comprises a piston 2 contained in piston chamber 28 which is connected through passage 29, chamber30, and passage 31 with the train pipe 32 and operates a main slide valve 33 and graduating slide valve 34 both contained in valve chamber 35 which is connected by a passage 36 with a pressure chamber 37. The quick action valve mechanism 3 comprises a piston 38 dividing the piston chamber into two chambers 39 and 40, the chamber 39 being connected to a passage 41 and chamber 40 to an atmospheric exhaust Said piston operates a quick action valve 43 contained in valve chamber 30 and is adapted to control communication from train pipe passage 31 to exhaust passage 42. The emergency valve mechanism 4 comprises a piston 44 contained in pistonchamber 44 which is connected to a passage 45 and said piston operates a valve 46 contained invalve chamber 47 which is connected to quick action chamber 48 through a passage 49. The emergency switch portion ,5 comprises a piston 50 contained in piston chamber 51 which is connected to passage 41 and said piston operates an electric switch 52 which controls the circuit of the emergency magnet 10. The protection valve device 6 comprises a piston having the chamber 53 at one side connected to a passage 54 leading to chamber 30 and having its opposite face open to an exhaust port 55. The

. high pressure emergency valve mechanism 7 comprises a piston provided with a valve seat 56 on oneside controlling communication from a passage 57 leading to the main reservoir valve chamber 17 to brake cylinder passage 23. The chamber at the opposite face of the piston 7 is connected to a paspressor 69.

sage 58 which leads to the seat of the application valve 16. The electric release magnet 8 operates a release valve 59 which con- .trols communication from a passage 60 leading to the seat of the equalizing slide valve 33 to an exhaust. port 61. The electric service valve 9 operates valve 62 for controlling communication from train pipe passage 45 to passage 63 leading to brake cylinder passage 23. The emergency magnet 10 operates a valve 64 for controlling communication from train pipe passage 65 to an exhaust ort 66.

As shown in Fig. 1 of the rawings, the car air brake equipment may comprise an electro-pneu'matic brake valve 67 at each end of the car and connected to the train pipe 32 and the main reservoir pipe line 19.

The main reservoir line is connected to a main reservoir 68 adapted to be charged .to the pressure carried by means of a com- On cars not provided witha compressor and main reservoir a storage reservoir 70 may be provided in place of the main reservoir. The electro-pneumatic control valve 71 is connected by pipe 72 as one or more brake cylinders 73.

For controlling the brakes electrically, the brake valve 67 is provided with contacts connected to supply train wire 74, service application Wire 75, release wire 76, emergency' Wire 77, and positive battery wire 78 is connected to supply wire 74. A negative battery wire 7 9 is also provided and a source of current 80 is connected across the positive and negative battery wires. The brake valve has the following positions; release, lap,

service and emergency, and these positions are the same for both electric and pneumatic control.

In operation, when the train pipe 32 is charged With fluid under pressure, air flows from passage 31, chamber 30 and passage 29 89, and passage 90. Air is also free to flow through port 91 in main slide valve 33, passage 92, cavity 93 in cap 89 and passage 94 to pipe 95 connectingwith a supplemental reservoir 96 and through ports 97 and 98 to a resistance increasing cavity 99 in the slide valve 33.

The size of passages through which the supplemental reservoir is charged is so proportioned with respect to the feed groove 86 that the time of charging is the same whether the supplemental reservoir is cut in or out, the increased fiow of air due to the added volume of the supplemental reservoir being provided by means of the additional flow through the passages 87, 88, and 90 directly from the train pipe to the pressure chamber. It should also be understood that fluid is supplied to the train pipe by means of the brake valve at a sufiicient rate to provide the additional fluid required when the supplemental reservoir is cut in.

Fluid from the train pipe also flows from chamber 30 through passage 54 to the face of the protection valve 6 and when the train pipe pressure attains a predetermined degree, the protection valve is quickly shifted to its outer position, owing to the exposure of the full area of the protection valve 'to train pipe pressure as soon as the same lifts from its seat, the opposite side of the valve being constantly open to atmospheric pressure. The protection valve being open, air flows from the train pipe through port 100 and passage 45 to piston chamber 44, forcing the emergency piston 44 to release posi tion, as shown in F ig. 3. The valve chamber 47 is then charged through feed gr0ove 101 and the quick action chamber 48 is also charged through passage 49. In this position, passage 41 connects piston chamber 51 with the quick action piston chamber 39 and these chambers are maintained at atmospheric pressure through port 102 in piston 38, which connects chamber 39 with chamber40, open to quick action exhaust passage 42; so that leakage into the chambers 51 and 39 can escape and thus prevent the possible unseating of the quick actionvalve 43 and the closing of the emergency switch 52.

Main reservoir air is contained in the chamber 17 and flows thence through port 103 and passage 58 to the spring side of the high pressure emergency valve 7. Main reservoir air also flows through passage 57 to the chamber at the opposite side of the valve 7 but as a portion of the area of the valve is open to the brake cylinder passage 23, the

high pressure emergency valve 7 is held ,to its seat with the assistance of spring'l04c.

If it is desired to effect an electric service application of the brakes, the brake valve handle is turned to service application position, which is also pneumatic service application position, and the electric circuit of the service magnet 9 is closed, so that said magnet is energized and the valve 62 is opened, as shown in Fig. 4. The release magnet circuit is also closed, so that the release magnet 8 is energized and the release valve 59 thereby closed. Fluid is thereupon vented from the train pipe passage 31, chamber 30, passage 54, port 100,passage 45, cavity 105 in cap 106, passage 107, and passage 63 to the brake cylinder passage 23.

Passage 63 is of such size as to limit the reduction is train pipe ressure to a rate insufficiently rapid to e ect the movement of the emergency piston 44, since the feed groove 101 is large enough to permit a corresponding reduction in the pressure in quick action chamber 48, but the rate of reduction is rapid enough to insure the movement of the equalizing piston 27 to its outer position.

The first or initial movement of the equalizing piston toward service application position closes the feed groove 86, the additional charging port 87, and the release port 108, opens service port 109, and cavity 110 in graduating valve 3-1 connects ports 98 and 111, thus exposing the area of the friction increasing cavity 99 to atmospheric pressure, so as to increase the differential of pressure required to move the equalizing slide valve to service application position.

While the electric release valve 59 is closed in making a service application of the brakes, the passage is still at atmospheric pressure and since the volume of this passage is very large as compared with the volume of the resistance increasing cavity 99, the effect of connecting said cavity with the passage 60 upon the preliminary movement of the graduating slide valve 34: is to subject said cavity to substantially atmospheric pressure.

One object of the above provision for increasing the frictional resistance of the valve is to reduce the sensitiveness of the equalizing valve sufficiently to prevent movement tending to cause an application of the brakes upon unintentional fluctuations in train pipe pressure due to variations in feed valve action or other causes. Another object is to obviate diiiiculty in releasing the brakes due to inability to secure a sufiicient differential on the equalizing piston, as might be the case where the brakes can be applied on a very small train pipe reduction.

Further movement of the equalizing piston 27 shifts the main slide valve 33 to service application position, in which communication is established from valve chamber 35through port 109 and passage M to apt lt plication chamber 15 and also application cylinder 12. Port 109 remains open until the pressure in the pressure chamber 37 has been reduced to a degree slightly less than that in the train pipe, when the equalizing piston 27 and graduating valve 31 are shifted so as to close the port 109. Fluid supplied to the application cylinder 12 causes the movement of application piston 11 to close the brake cylinder exhaust port 112 through the movement of release valve 20 and connect port 113 in application valve 16 with chamber 21. Air from the main reservoir is thus permitted to flow to the brake cylinder from chamber 21 through passages 22 and 23. Valve chamber 21 is connected to chamber 13 by means of a feed groove 111 around piston 26, in service application position, so that the pressures in said chambers are maintained equal in service applications.

Flow of air from the main reservoir to the brake cylinder continues until the pressure in the brake cylinder is substantially equal to the pressure in the application cylinder' 12, when the graduating spring 115 shifts ehe application valve mechanism to service The pressures on opposite sides of the pisbe any loss of pressure on either side of the piston the same will be moved toward the lower pressure, thus causing either a slight increase or a reduction in the pressure in chamber 21 and the brake cylinder. The service application magnet ma either be held energized, to hold the app ication valve 16 open and permit full equalization of train pipe and brake cylinder pressures, or the same may be energized for a few seconds only to cause a partial application of the brakes.

If it is desired to release the brakes, the brake valve handle is moved to release position, in which the release magnet circuit is open, so that the release magnet 8 is deenergized and the release valve 59 is opened. The train pipe port in the brake valve is also open so as to restore the train pipe pressure to normal. The equalizing piston 27 is forced to release position by the increase in train pipe pressure and it should be noted that first movement of the piston 27 toward release position causes port 97 to register with port 98 so that fluid from the pressure chamber flows into the resistance increasing cavity 99, and the area of this cavity being thus balanced the resistance of the valve to movement is reduced, and consequently the equalizing valve mechanism is adapted to release at a lower differential than is required to effect an application of the brakes. I K

In release position of the equalizing valve position, closing the application port ton 11 are now balanced but if there should mechanism,- the application chamber 15 and application cylinder 12 are connected to the exhaust through passage 14, port 108, cavity 110, port 111, and passage 60. The pressure on piston 11 being released, the piston is shifted to release position inwhich fluid in the brake cylinder is released through the cavity 105, and passage 65.

The reduction in train pipe pressure causes the equalizing piston to shift to emergency position, which is the same as service application position. The protection valve device 6 is also shifted outwardly, closing the train pipe passage 54 and opening communication from passage 45 through a port 116 to the atmospheric port 55. The pressure in chamber 44 is thus quickly reduced and the emergency piston is shifted to emergency position in which the slide valve 46 uncovers a port 117 leading to passage 41. Fluid is then supplied from the quick action chamber 48 to the switch piston 50 and also to the quick action piston 38, thus I causing the train pipe vent valve 43 to open and vent air from the train pipe and the emergency switch 52 to close, so as to insure the closing of the circuit of the emergency magnets 10. The quick action valve mechanismand the emergency switch remain in emergency position until the quick action chamber 48 drains to the atmosphere through the small port 102 in the quick action piston 38, then the quick action valve mechanism and the switch mechanism are returned to normal position by their respec tive springs. Chamber 13 is also connected to the. atmosphere through passage 118, cavity 119 in slide valve 33, passage 120, cavity 121 in emergency valve 46, and exhaust port 122. I I

With fluid from the pressure chamber flow-ing to the application cylinder 12 and fluid in chamber 13 vented to the atmosphere, the application piston is quickly shifted to its extreme position in which the seal 123 is seated and the groove 114 is closed. In this position, port 113 opens communication for supplying main reservoir air from valve chamber 17 to the valve chamber 21 and the brake cylinder as in service applications, and in addition, passage 58 lead-. ing to one side of the high pressure emergency valve 7 is connected to the atmosphere through cavity 124 in valve 16 and passage 125. As main reservoir pressure is on the opposite side of the valve 7, the same is shifted to open a large direct opening from the main reservoir supply passage 57 to the brake cylinder passage 23. With chamber 13 open to the atmosphere, the area of the piston exposed to the pressure of the application cylinder is considerably greater than the area exposed to the pressure in chamber 21 and consequently the full main reservoir pressure may be retained in the brake cylinder if desired, although the full equalized pressure in the application cylinder may be much less than the main reservoir pressure.

In releasing the brakes after an emergency application, upon increasing the train pipe'pressure, the protection valve 6 is first shifted to release position and then fluid is admitted from the train pipe to chamber 44, so as to shift the emergency piston 44 to release position. Further increase in train pipe pressure shifts the equalizing piston 27 to release position, which in turn effects the movement of the application piston to release position. The opposing pressures on the high pressure emergency piston are then balanced by the admission of main reservoir air through port 103 and passage 58 to the spring side of same, so that the spring 104 causes the seating thereof in normal position.

The release of the brakes may be graduated electrically by moving the brake valve handle between electric release and electric lap positions. The train pipe is charged in the release position, so that the equalizing piston 27 is shifted to release position, but the release magnet valve 59 is first opened when the brake valve is-moved to release position and then closed when the brake valve is moved to lap position, so that the pressure in the application cylinder is reduced a few pounds at each graduation. As will be understood from the description of operation previously given, the application piston is moved to open the brake cylinder exhaust and release air from the brake cylinder until the brake cylinder pressure substantially equals the reduced application cylinder pressure. Further graduations in brake cylinder pressure may be made in the same manner.

In case the electrical features of the control valve become inoperative from any cause, the brakes will be operated pneumatically by variations in train pipe pressure through the usual movements of the brake valve, the positions of the brake valve being the same for both electric and pneumatic operation.

Provision is made for pneumatic graduated release by providing a supplemental lease position of the equalizing valve mech-. anism, the increase in pressure in the valve chamber 35 thus produced then operates to .to remain in service application position,

the brakes would first be applied in service until the brake cylinder pressure attained the equalizing pressure and then upon reduction in train pipe pressure-below that of the protection valve spring 126, the protection valve 6 is shifted to emergency position, thus causing fluid to be vented from the emergency piston 44, so that the same is shifted to emergency position to cause an emergency application of the brakes as heretofore described. a

While the control valve is designed more particularly for tractionservice, the same may also be employed in steam rpad service, but as the basis upon which the braking power is calculated is usually different for steam roads, means are provided for reducing this difference to a minimum. For example, the usual basis for braking power in steam road service is 90% on 60 pounds brake cylinder pressure, while the service for which the control .valve is normally de-- signed, 100% on pounds brake cylinder pressure is employed.

In order to eliminate this diflerence in braking power as much as possible, an additional application chamber 127 is provided, which when desired may be connected to the usual application chamber 15 by adjusting the equalizing piston cap 128 so that a cavity 129 therein connects passage 130 leading to application chamber passage 14 with passage 131 leading to the additional application chamber 127, as shown in lFi 7.

luid from the pressure chamber therefore equalizes into the extra volume provided by the additional appllcation chamber in making a service application otthe brakes, so that the equalizing pressure is reduced. In service, where no main reservolr line is provided, the reservoir must be" charged from the train pipe and for th s purpose, a port 132 is provided whlch is open to the train pipe only in the release position of the equalizing p1ston27 and in the steam road position of the equal z ng cap 128, a cavity 133 therein contaming check valve 134 connects port 132 with passage 135 opening into. the valve chamber 17. This communication for charging the main reservoir is restricted so that the samecannot take air from the train pipe at a rate suificient to eflect the usual braking operations.

Having now described my invention, What I claim as new and desire to secure by Letters Patent, is

1. In a fluid pressure brake, the combination with an application valve device having a differential piston subject to the op posing pressures of an application chamber and the brake cylinder, for controlling the admission of fluid to the brake cylinder and an automatic valve device subject to variations in train pipe pressure for controlling thepressure in said application chamber, of an emergency valve mechanism operating upon a sudden reduction in train pipe pressure for effecting an emergency application of the brakes and a passage-way controlled by the movement of both the automatic valve device and the emergency valve mechanism to emergency position for venting fluid from one side of said diflerentialpiston to assist in holding the application valve device in emergency position.

2. In a fluid pressure brake, the combination with an application chamber, an application valve device comprising a valve for supplying fluid to the brake cylinder, a differential piston having one head subject to the pressure of an application chamber and the other head subject to brake cylinder pressure, and. an equalizing port around the second head for normally equalizing the fluid pressures on opposite sides thereof, and an automatic valve device operated by variations in train pipe pressure for controlling the pressure in sa1d application chamber, of an emergency valve mechanism operating upon a sudden reduction in train pipe pressure for efl'ecting an emergency application of the brakes and a passageway controlled by the movement of the automatic valve device and the emergency valve mechanism to emergency position for venting fluid from the brake cylinder side of said difl'erential piston to' thereby assist in holding the application valve device in emergency position.

' 3. In a fluid pressure brake, the combination with an application chamber and a valve device operated by the pressure in the application chamber for supplying fluid to the brake cylinder, of a valve mechanism controlled by said application valve device for venting fluid from a source of pressure said application valve device for normally supplying fluid to one side of said valve mechanism, said application valve device being adapted in emergency position to connect said portto the atmosphere.

' 5. In a fluid pressure brake, the combination with an application chamber and a valve device operated by the pressure in the application chamber for supplying fluid to the brake cylinder, of an automatic valve devic'e subject to the opposing pressures of the train pipe and a pressure chamber for controlling the admission of fluid from the pressure chamber to the application chamber and an additional application chamber adapted to be connected to the regular application chamber.

6. In a fluid pressure brake, the combination with an application chamber, a valve mechanism operated by the pressure in said application chamber for efiecting an application of the brakes, and an automatic valve device operated upon a reduction in train pipe pressure for supplying fluid to said application chamber, of electrically controlled means for eflecting a reduction in train pipe pressure and for controlling the exhaust of fluid from said application chamber.

7. Ina fluid pressure brake, the combination with a brake cylinder, of an application chamber, a valve mechanism comprising a piston subject to the opposing pressures of the brake cylinder and said application chamber and avalve carried by said piston for supplying fluid to the brake cylinder to eflect a service application of the brakes in one position and for supplying fluid to effect an emergency pplication of the brakes in another position.

8. In a fluid pressure brake, the combination with a brake cylinder, of an application chamber, a valve mechanism comprising a piston subject to the opposing pressures of the brake cylinder and said application chamber and a slide valve carried by said piston for supplying fluid to the brake cylinder to eflect a service application of the brakes upon a gradual reduction in train pipe pressure in one position and for efi'ecting an emergency application of the brakes upon a sudden reduction in train pipe pres sure in another'position.

9. In a fluid ressure brake, the.combina. tion with a bra e cylinder, a train pipe, an application chamber, a valve mechanism .operated by the pressure in the application chamber for supplying'fluid to the brake cylinder in one position, and an automatic valve device operating upon a reduction in train pi e ressure for supplying fluid to the application chamber, of means operating upon a sudden reduction in train pipe pressure for shifting said valve mechanism to another position for efl'ecting an emergency application of the brakes.

10. In a fluid pressurebrake, the combination with a brake cylinder, a train pipe, an application chamber, a valve mechanism operated by the pressure in the application chamber for supplying fluid to the brake cylinder in one position, and an automatic valve device operating upon a reduction in train pipe pressure for supplying fluid to the application chamber, of an emergency valve device for supplying fluid to the brake cylinder in an emergency application of the brakes and means operating upon a sudden reduction in train pipe pressure for shifting said application valve mechanism to'another position for effecting the operation of said emergency valve device.

11. In a fluid pressure brake, the combination with a brake cylinder, train pipe, 'an application chamber, a valve mechanism operated by the pressure in the application chamber for supplying fluid to the brake cylinder in one position, and an automatic valve device operating upon a reduction in train pipe pressure for supplying fluid to the application chamber, of an emergency valve device for supplying fluid to the brake cylinder in an emergency application of the brakes, means operating upon a sudden reduction in train pipe pressure for shifting said application valve mechanism to another position for eflectin the operation of said emergency valve device, and electrically controlled means for eflecting a sudden reduction in train pipe pressure.

12. In a fluid pressure brake, the combination with a brake cylinder, a train pipe, an application chamber, a valve mechanism operated by the pressure in the application chamber for supplying fluid to the brake cylinder, and an automatic valve device operating upon a reduction in train pipe pressure for supplying fluid to the application chamber, of means operating upon a sudden reduction in train pipe pressure for efiecting an emergency application of the brakes and electrically controlled means for effecting a gradual reduction in train pipe pressure and a sudden reduction in train pipe pressure.

13. In a fluid pressure brake, the combination with a brake cylinder, a train pipe, an application chamber, a valve mechanism operated by the pressure in' the application chamber for supplying fluid to the brake cylinder, and an automatic valve device operating upon. a reduction in train ipe pressure for'supplying fluid to the app ication chamber, of means operating upon .a sudden reductionin train pipe pressure for effecting an emergency application of the brakes, an electrically controlled valve-for efiecting a gradual reduction in train pipe niaaoea pressure, and an electrically controlled valve for efl'ecting a sudden reduction in train pipe pressure.

14. In a fluid pressure brake, the combination with a brake cylinder, a train pipe, an application chamber, a valve mechanism operated by an increase in pressure in the application chamber for supplying fluid to the brake cylinder in one position, and an automatic valve device operating upon a reduction in train pipe pressure for supplying fluid to the application chamber, of an emergency valve mechanism operating upon a sudden reduction in train pipe pressure'for eflecting the movement of said application valve mechanism to another position and means operated by said valve mechanism in the last mentioned position for supplying fluid to, the brake cylinder with increased pressure.

15. In a fluid pressure brake, the combination with a brake cylinder, a train pipe, an application chamber, a valve mechanism opera'ttedby an increase in pressure in the application chamber for supplying fluid to the brake cylinderin one'position,,and an automatic valve device adapted upon a gradual reduction in train pipe pressure to make full traverse and open communication for supplying fluid to the application chamber to eflect the movement of the application valve mechanism to one position for effecting a service application of the brakes, of a separate valve mechanism operating upon a sudden reduction in train pipe pressure to eflect the movement of said application valve mechanism to another position in which an' emergency application of the brakes is eflected.

In testimony whereof l have hereunto set my hand.

WALTER V. TURNER.

Witnesses A. M. CLEMENTS, B. A. U.

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